Trampoline forwarding

lightning/src/chain/channelmonitor.rs

@@ -2626,6 +2626,7 @@ impl<Signer: EcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 				let outbound_payment = match source {
 					None => panic!("Outbound HTLCs should have a source"),
 					Some(&HTLCSource::PreviousHopData(_)) => false,
+					Some(&HTLCSource::TrampolineForward { .. }) => false,
 					Some(&HTLCSource::OutboundRoute { .. }) => true,
 				};
 				return Some(Balance::MaybeTimeoutClaimableHTLC {
@@ -2835,6 +2836,7 @@ impl<Signer: EcdsaChannelSigner> ChannelMonitor<Signer> {
 					let outbound_payment = match source {
 						None => panic!("Outbound HTLCs should have a source"),
 						Some(HTLCSource::PreviousHopData(_)) => false,
+						Some(HTLCSource::TrampolineForward { .. }) => false,
 						Some(HTLCSource::OutboundRoute { .. }) => true,
 					};
 					if outbound_payment {
@@ -3494,7 +3496,8 @@ impl<Signer: EcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 					}
 				}));
 			}
-			self.counterparty_fulfilled_htlcs.insert(*claimed_htlc_id, *claimed_preimage);
+			let claimed = claimed_htlc_id.clone();
+			self.counterparty_fulfilled_htlcs.insert(claimed, *claimed_preimage);
 		}
 
 		Ok(())

lightning/src/events/mod.rs

@@ -539,6 +539,14 @@ pub enum HTLCHandlingFailureType {
 		/// Short channel id we are requesting to forward an HTLC to.
 		requested_forward_scid: u64,
 	},
+	/// We couldn't forward to the next Trampoline node. That may happen if we cannot find a route,
+	/// or if the route we found didn't work out.
+	FailedTrampolineForward {
+		/// The node ID of the next Trampoline hop we tried forwarding to.
+		requested_next_node_id: PublicKey,
+		/// The channel we tried forwarding over, if we have settled to one.
+		forward_scid: Option<u64>,
+	},
 	/// We couldn't decode the incoming onion to obtain the forwarding details.
 	InvalidOnion,
 	/// Failure scenario where an HTLC may have been forwarded to be intended for us,
@@ -572,6 +580,10 @@ impl_writeable_tlv_based_enum_upgradable!(HTLCHandlingFailureType,
 	(4, Receive) => {
 		(0, payment_hash, required),
 	},
+	(5, FailedTrampolineForward) => {
+		(0, requested_next_node_id, required),
+		(2, forward_scid, option),
+	}
 );
 
 /// The reason for HTLC failures in [`Event::HTLCHandlingFailed`].